1. Field of the Invention
The present invention relates to a gear synchronizer for power transmissions, and more particularly, but not exclusively, to a gear synchronizer of the type which comprises a gear member rotatable on a transmission shaft, a spline piece formed thereon with external splines and provided on a hub portion of the gear member for rotation therewith, a hub member formed thereon with external splines and mounted on the transmission shaft for rotation therewith, a clutch sleeve encircling the hub member and having an internal frustoconical portion formed at one side thereof and internal splines in continual engagement with the external splines of the hub member, the clutch sleeve being axially shiftable toward and away from the gear member to be engaged at the internal splines thereof with the external splines of the spline piece, and a synchronizer ring encircling the spline piece and having a radial projection axially movable in a corresponding recess formed in the spline piece and an external frustoconical surface for frictional engagement with the frustoconical portion of the clutch sleeve, the synchronizer ring being loaded radially outwardly by means of a spring to be retained in a neutral position where it is disengaged from the frustoconical portion of the clutch sleeve.
2. Description of the Prior Art
In Japanese Patent Publication No. 51-48540, there has been proposed such a gear synchronizer as described above, wherein the external frustoconical surface of the synchronizer ring can be formed larger in diameter than an internal frustoconical surface of a synchronizer ring in a conventional synchronizer of the Borg-Warner type. In operation of the gear synchronizer, the synchronizer ring acts to effect relatively large synchronous action or capacity in comparison with the synchronizer of the Borg-Warner type. In the case that the gear synchronizer is designed to obtain the same synchronous capacity as that of the Borg-Warner type synchronizer, and the synchronizer ring can be constructed small in size to reduce an axial displacement amount of the clutch sleeve when shifting in order to minimize the shift stroke of a manual shift lever. In the case that the shift stroke of the manual shift lever is determined in the same amount as that in the Borg-Warner type synchronizer, the lever ratio of the manual shift lever can be increased to reduce the operator's effort applied to the shift lever for shifting the clutch sleeve.